51个木麻黄无性系遗传多样性的ISSR分析

采用ISSR分子标记对51个木麻黄无性系进行遗传多样性和亲缘关系分析。结果表明:ISSR适用于木麻黄无性系遗传分析,22个ISSR引物在供试无性系中共扩增出199个位点,多态性位点154个,多态位点百分率为77.4%;平均有效等位基因数为1.5,Nei’s基因多样性指数为0.174 1 0.389 1,Shannon信息指数为0.273 20.556 0,相似系数为0.467 3 0.995 0,平均为0.743 0,表明供试无性系的遗传基础已相对比较狭窄。ISSR聚类分析表明:参试无性系并不能按来源地各自单独聚为1类,无性系亲缘关系的远近与来源相关不大;在相似系数为0.678时,可将所有供试材料分为2大类群;亲缘关系树状图在分子水平上显示了供试无性系间的亲缘关系,为今后木麻黄无性系的推广应用及育种亲本的选配提供了理论依据。

Analysis of Genetic Diversity and Relationship Among 51 Casuarina Superior Clones by Using ISSR Markers

Casuarinas are important for coastal protection purpose in China. In recent years, many Casuarinas clones have been developed. The knowledge on genetic diversity and relationship of these clones is critical to guide Casuarinas breeding, but still limited. In this study, twenty-two selected ISSR primers were used to amplify the tested clones. A total of 199 bands were obtained in which 154 bands (77.4%) were polymorphic. The average effective number of alleles was 1.5. The Nei's gene diversity indices (H) ranged from 0.174 1 to 0.389 1 and the Shannon's information index (I) ranged from 0.273 2 to 0.556 0. The genetic similarity coefficients among the tested clones ranged from 0.467 3 to 0.995 0, with an average of 0.743 0. The results showed that the genetic differences among the 51 clones were relatively little. The cluster analysis based on ISSR markers revealed that the 51 clones could not be cluster according to their origin and there were no correlation between genetic relationship and geographical origin. The 51 clones of Casuarinas could be divided into 2 groups when the similarity coefficient was 0.678. The genetic relationship of all the 51 clones revealed by the ISSR dendrogram would be of great help for genotype screening in afforestation project and parental selection in Casuarinas breeding.